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oldkoot

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Newbie Mopar owner question.I have a 67 Dart with a 273, Edelbrock 500 cfm carburetor.When cold it starts perfect , just tap the gas to set the choke and starts fine. When the engine is at operating temperature and shut off and then try to restart after say 10 minutes it acts like it's flooded but the throttle plates are dry(no gas leaking from the pump nozzles,checked float level and fuel pump pressure-OK). If you just crank it over without touching the gas it wont start but with a little throttle it starts right up. Is it normal for a Mopar to need a little throttle for starting when hot? Sorry if it sounds like a dumb question but every other carb'd car I've owned you didn't need to touch the gas when warm?
 
Yeah mines that way too. I've tried everything I can think of and it still does it. I never had any trouble 20 yrs. ago with any car doing this. I kinda think it maybe the way they're formulating fuel nowadays.

BTW: It's not just Mopars. I have a buddy with a couple chevy trucks and they do it too.
 
I'm almost certain it has to do with fuel formulation. Modern gas evaporates very quickly, and when your car is warmed-up and sits for a while on a decently warm day, the gas in your float chambers evaporates and empties your carb. So when you come back to start the car, you have to crank it for a couple seconds to get the fuel pump to fill the float chambers and then get fuel into the engine. My '70 Duster does the exact same thing, and it's especially worse on hot days. Nothing we can do about it either; in fact, this quicker-evaporating gas probably gives us better fuel economy and power than olde-tyme gas because of better atomization in the carb venturis.
 
HI mopar people ??(m/f) new to forum? i have a 72 valiant 340 new motor !! this car is a auto 904 . 600 CFM (VSD) I think i may have timing to far back with cam in it . just had a little race with it.valves were not happy ???
 
limetwist said:
HI mopar people ??(m/f) new to forum? i have a 72 valiant 340 new motor !! this car is a auto 904 . 600 CFM (VSD) I think i may have timing to far back with cam in it . just had a little race with it.valves were not happy ???
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Try posting another thread about your problem. You will get more replies that way and won't be "hijacking" another member's thread.:-D
 
Oldkoot and Fishy,

Have you guys tried using a insulated spacer to keep the carb from boiling out?
 
limetwist said:
sorry still not sure how to post .. (limetwist)!
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Limetwist if you want to start a new tread just look in the upper left hand corner of the forum your in and there is a box there that says NEW TOPIC. Click on it and it'll open up a new thread page for you that you can title according to your question. Then just type in the question in the box below it. Also make sure you post it in the correct forum. i.e. General forum for most any question or statement related or unrelated to cars, Transmission and drivetrain forum for a question or answer about a trans or rearend problem. Good luck and welcome to the board.
 
Gas is not the issue, it's not boiling or evaporating, it wants more air to start when hot thus having to hold the gas pedal down about 1/4.
 
oldkoot said:
Gas is not the issue, it's not boiling or evaporating, it wants more air to start when hot thus having to hold the gas pedal down about 1/4.
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Or more fuel, as you tap the accelerator you're activating the accelerator pump. What would happen if you were to squirt just a bit of fuel in there when it's hot? Think it would fire right up?

Could also be fuel fumes collecting within the air cleaner housing from the carb vent as the fuel evaporates from a heated carb. Open the throttle, let it crank until the it starts pulling fresh air into the carb. What would happen if you removed the air cleaner while the engine was hot? Does it fire right up?
 
With the air cleaner on or removed it acts the same. If you don't touch the gas, it cranks over but won't fire, you would almost think it was flooded but when you look into the carb the butterflies are dry. I've also pulled the plugs to confirm and they are dry.If you give it a pump of gas but don't hold the throttle open the same thing, it won't fire. The fuel line and carb body are not hot enough that you can't hold your hand on them.The idle speed is set for 600 in drive so the throttle blades are not open very far, that's why I'm thinking it needs to draw more air.
 
oldkoot said:
With the air cleaner on or removed it acts the same. If you don't touch the gas, it cranks over but won't fire, you would almost think it was flooded but when you look into the carb the butterflies are dry. I've also pulled the plugs to confirm and they are dry.If you give it a pump of gas but don't hold the throttle open the same thing, it won't fire. The fuel line and carb body are not hot enough that you can't hold your hand on them.The idle speed is set for 600 in drive so the throttle blades are not open very far, that's why I'm thinking it needs to draw more air.
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Damn, *tilts head like dog* I wonder why that is? Anyone else have any input?
 
My 67 273 was the same except 2V. I installed a 1/4" spacer and that fixed it. Mine was boiling dry. You could install an electric fuel pump and turn on the ignition for 8 or 10 seconds before cranking it.
 
MVRCorp said:
My 67 273 was the same except 2V. I installed a 1/4" spacer and that fixed it. Mine was boiling dry. You could install an electric fuel pump and turn on the ignition for 8 or 10 seconds before cranking it.
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oldkoot says the carb isn't dry though. Odd.
 
OK, just had a thought (it happens once in a while but not very often, lol). What happens if you were to plug the PCV inlet for the carb while it was hot? Would it fire right up? I do know that it would run like crap if it did, but my thought was that it may be pulling expanding gases from the crankcase rather than pulling air/fuel through the carb.
 
Mine does this as well and have gone through the same checks it has a brand new carb on it too. I will try some different things this weekend and see if we can figure this one out.
 
oldkoot said:
With the air cleaner on or removed it acts the same. If you don't touch the gas, it cranks over but won't fire, you would almost think it was flooded but when you look into the carb the butterflies are dry. I've also pulled the plugs to confirm and they are dry.If you give it a pump of gas but don't hold the throttle open the same thing, it won't fire. The fuel line and carb body are not hot enough that you can't hold your hand on them.The idle speed is set for 600 in drive so the throttle blades are not open very far, that's why I'm thinking it needs to draw more air.
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I observed the same thing on my buddies Chevy pickup and my Cuda except my idle is set at 800 in drive due to the large cam. My buddies 454 is set at 650 in drive. At one time I also had 1/32 holes drilled in the primary butterflies to try to get it to idle better but that caused it to run rich off idle so I replaced the butterflies with new ones. It does the same no matter what butterflies were in it. When I first put my car together I thought it might be electrical but I checked and it fires right away. Just don't start unless you hold the pedal down some. When it was cold out it didn't do it. The hotter it gets the worse it is. I can't try an insulator on mine because I have no hood clearance as it is but we did try one on my buddies truck and it made no difference. Also note my car has an electric fuel pump also so I'm sure the bowls are not dry when it's warm. I can't come up with an explanation other than it may be fuel formulation.
 
my edelbrock carb does the same, and if you let it sit for longer than a week or two without starting it takes a fair bit of pumping the pedal to get er to go.

Buddy has a autolite (holley) on his mustang and didn't start it all winter, it fired up on try just touching the key....... My engine took quite a bit of coaxing after sitting over the winter.

Maybe its just the carb design.
 
Brambles said:
my edelbrock carb does the same, and if you let it sit for longer than a week or two without starting it takes a fair bit of pumping the pedal to get er to go.

Buddy has a autolite (holley) on his mustang and didn't start it all winter, it fired up on try just touching the key....... My engine took quite a bit of coaxing after sitting over the winter.

Maybe its just the carb design.
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Identical findings here also.

Holley carb solved my problem. Hot or cold, sit for weeks at at time...starts right up.

Almost sounds like an air lock problem in the bowls. Maybe plugged air bleeds?

I think the difference with the Holley is the bowls are on the ends instead of directly on top of a hot intake????

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I have not experienced this with a Holley either. Fishy, are you running a Holley?
 
I've had this on many mopars,,all eddy's,,,,my valiant now starts a little harder when warm too,,,but my sons 72 dart,,,stout 318,,,has 1 inch spacer with eddy and cold air intake,,,,,fires every time
 
I think it'd an Eddy/Carter thing, as well. 340 w/Holley in the Duster starts fine, no matter what. 440 w/AVS in the Chrysler needs the throttle open to start hot. Both have phenolic spacers.

But then again, I remember the 440 used to do it with the old stock Holley before. But it had other issues then too....
 
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